Monocyte Differentiation and Macrophage Polarization in Circulation in Response to Macronutrient Intake in Healthy Humans: A Randomized Clinical Study

Thirty-six normal healthy adult volunteers of normal weight were recruited into the study. All were normotensive, had a normal lipid profile, normal renal and liver function tests, and were not on any medications. All subjects gave their written, informed consent. Institutional Review Board (IRB) of the Ministry of National Guard Health Affairs (MNGHA) approved the study protocol. The 36 participants were randomly assigned by the primary investigator (PI) following simple randomization procedure (computerized random numbers) to three different groups, each received one type of macronutrient (Glucose, whey proteins or lipids). Following an overnight fast, a baseline blood sample was taken. Subjects were then given either 300 calories of glucose (NERL Trutol 75) or lipids (90 grams whipping cream, 31.5 grams fat, 1.7 grams protein and 2.25 grams carbohydrate) or protein (Isopure unflavored Whey proteins isolate (WPI) powder containing 26 grams per serving of 100% WPI, stripped of fat, carbs, fillers, sugars and lactose) solution over 5 minutes. Cream and protein preparations were diluted with water up to 300 mL solutions. Further blood samples were obtained at 1, 2 and 3 hours after the macronutrient intake. Subjects, either one week before or after the macronutrient challenge, were given 300 mL of water to drink in the fasting state. Blood samples were obtained before and at 1, 2 and 3 h after water intake as well. Each subject served as his/her own control and was randomly given macronutrient or water intake.